Merge "Zen: Pull next-alarm tracking out into separate helper." into lmp-mr1-dev

automerge: 7936ca3

* commit '7936ca36d9dfd620df0bfead6c79b5eddc761c20':
  Zen: Pull next-alarm tracking out into separate helper.

4 files changed, 340 insertions, 205 deletions

diff --git a/services/core/java/com/android/server/notification/ConditionProviders.java b/services/core/java/com/android/server/notification/ConditionProviders.java
index 3ff9ff4b37d1..a1085d32580b 100644
--- a/services/core/java/com/android/server/notification/ConditionProviders.java
+++ b/services/core/java/com/android/server/notification/ConditionProviders.java
@@ -51,6 +51,7 @@ public class ConditionProviders extends ManagedServices {
             = new ArrayMap<IBinder, IConditionListener>();
     private final ArrayList<ConditionRecord> mRecords = new ArrayList<ConditionRecord>();
     private final CountdownConditionProvider mCountdown = new CountdownConditionProvider();
+    private final NextAlarmTracker mNextAlarmTracker;
     private final DowntimeConditionProvider mDowntime = new DowntimeConditionProvider();
     private final NextAlarmConditionProvider mNextAlarm = new NextAlarmConditionProvider();
 
@@ -63,6 +64,7 @@ public class ConditionProviders extends ManagedServices {
         mZenModeHelper = zenModeHelper;
         mZenModeHelper.addCallback(new ZenModeHelperCallback());
         loadZenConfig();
+        mNextAlarmTracker = new NextAlarmTracker(context);
     }
 
     @Override
@@ -101,6 +103,7 @@ public class ConditionProviders extends ManagedServices {
         mCountdown.dump(pw, filter);
         mDowntime.dump(pw, filter);
         mNextAlarm.dump(pw, filter);
+        mNextAlarmTracker.dump(pw, filter);
     }
 
     @Override
@@ -111,6 +114,7 @@ public class ConditionProviders extends ManagedServices {
     @Override
     public void onBootPhaseAppsCanStart() {
         super.onBootPhaseAppsCanStart();
+        mNextAlarmTracker.init();
         mCountdown.attachBase(mContext);
         registerService(mCountdown.asInterface(), CountdownConditionProvider.COMPONENT,
                 UserHandle.USER_OWNER);
@@ -121,20 +125,13 @@ public class ConditionProviders extends ManagedServices {
         mNextAlarm.attachBase(mContext);
         registerService(mNextAlarm.asInterface(), NextAlarmConditionProvider.COMPONENT,
                 UserHandle.USER_OWNER);
-        mNextAlarm.setCallback(new NextAlarmConditionProvider.Callback() {
-            @Override
-            public boolean isInDowntime() {
-                return mDowntime.isInDowntime();
-            }
-        });
+        mNextAlarm.setCallback(new NextAlarmCallback());
     }
 
     @Override
     public void onUserSwitched() {
         super.onUserSwitched();
-        if (mNextAlarm != null) {
-            mNextAlarm.onUserSwitched();
-        }
+        mNextAlarmTracker.onUserSwitched();
     }
 
     @Override
@@ -572,6 +569,23 @@ public class ConditionProviders extends ManagedServices {
                 mZenModeHelper.setZenMode(Global.ZEN_MODE_OFF, "downtimeExit");
             }
         }
+
+        @Override
+        public NextAlarmTracker getNextAlarmTracker() {
+            return mNextAlarmTracker;
+        }
+    }
+
+    private class NextAlarmCallback implements NextAlarmConditionProvider.Callback {
+        @Override
+        public boolean isInDowntime() {
+            return mDowntime.isInDowntime();
+        }
+
+        @Override
+        public NextAlarmTracker getNextAlarmTracker() {
+            return mNextAlarmTracker;
+        }
     }
 
     private static class ConditionRecord {
diff --git a/services/core/java/com/android/server/notification/DowntimeConditionProvider.java b/services/core/java/com/android/server/notification/DowntimeConditionProvider.java
index 881c9ad7fb1a..24fd155ee234 100644
--- a/services/core/java/com/android/server/notification/DowntimeConditionProvider.java
+++ b/services/core/java/com/android/server/notification/DowntimeConditionProvider.java
@@ -298,5 +298,6 @@ public class DowntimeConditionProvider extends ConditionProviderService {
 
     public interface Callback {
         void onDowntimeChanged(int downtimeMode);
+        NextAlarmTracker getNextAlarmTracker();
     }
 }
diff --git a/services/core/java/com/android/server/notification/NextAlarmConditionProvider.java b/services/core/java/com/android/server/notification/NextAlarmConditionProvider.java
index 4a29573a1859..35bbaa053465 100644
--- a/services/core/java/com/android/server/notification/NextAlarmConditionProvider.java
+++ b/services/core/java/com/android/server/notification/NextAlarmConditionProvider.java
@@ -16,34 +16,23 @@
 
 package com.android.server.notification;
 
-import android.app.ActivityManager;
 import android.app.AlarmManager;
-import android.app.PendingIntent;
 import android.app.AlarmManager.AlarmClockInfo;
-import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
 import android.net.Uri;
-import android.os.Handler;
-import android.os.Message;
-import android.os.PowerManager;
-import android.os.UserHandle;
 import android.service.notification.Condition;
 import android.service.notification.ConditionProviderService;
 import android.service.notification.IConditionProvider;
 import android.service.notification.ZenModeConfig;
-import android.util.TimeUtils;
-import android.text.format.DateFormat;
 import android.util.Log;
 import android.util.Slog;
+import android.util.TimeUtils;
 
 import com.android.internal.R;
 import com.android.server.notification.NotificationManagerService.DumpFilter;
 
 import java.io.PrintWriter;
-import java.util.Locale;
 
 /**
  * Built-in zen condition provider for alarm-clock-based conditions.
@@ -62,33 +51,21 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
     private static final String TAG = "NextAlarmConditions";
     private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
 
-    private static final String ACTION_TRIGGER = TAG + ".trigger";
-    private static final String EXTRA_TRIGGER = "trigger";
-    private static final int REQUEST_CODE = 100;
     private static final long SECONDS = 1000;
     private static final long MINUTES = 60 * SECONDS;
     private static final long HOURS = 60 * MINUTES;
-    private static final long NEXT_ALARM_UPDATE_DELAY = 1 * SECONDS;  // treat clear+set as update
-    private static final long EARLY = 5 * SECONDS;  // fire early, ensure alarm stream is unmuted
-    private static final long WAIT_AFTER_CONNECT = 5 * MINUTES;// for initial alarm re-registration
-    private static final long WAIT_AFTER_BOOT = 20 * SECONDS;  // for initial alarm re-registration
+
     private static final String NEXT_ALARM_PATH = "next_alarm";
     public static final ComponentName COMPONENT =
             new ComponentName("android", NextAlarmConditionProvider.class.getName());
 
     private final Context mContext = this;
-    private final H mHandler = new H();
 
-    private long mConnected;
-    private boolean mRegistered;
-    private AlarmManager mAlarmManager;
-    private int mCurrentUserId;
+    private NextAlarmTracker mTracker;
+    private boolean mConnected;
     private long mLookaheadThreshold;
-    private long mScheduledAlarmTime;
     private Callback mCallback;
     private Uri mCurrentSubscription;
-    private PowerManager.WakeLock mWakeLock;
-    private long mBootCompleted;
 
     public NextAlarmConditionProvider() {
         if (DEBUG) Slog.d(TAG, "new NextAlarmConditionProvider()");
@@ -97,14 +74,9 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
     public void dump(PrintWriter pw, DumpFilter filter) {
         pw.println("    NextAlarmConditionProvider:");
         pw.print("      mConnected="); pw.println(mConnected);
-        pw.print("      mBootCompleted="); pw.println(mBootCompleted);
-        pw.print("      mRegistered="); pw.println(mRegistered);
-        pw.print("      mCurrentUserId="); pw.println(mCurrentUserId);
-        pw.print("      mScheduledAlarmTime="); pw.println(formatAlarmDebug(mScheduledAlarmTime));
         pw.print("      mLookaheadThreshold="); pw.print(mLookaheadThreshold);
         pw.print(" ("); TimeUtils.formatDuration(mLookaheadThreshold, pw); pw.println(")");
         pw.print("      mCurrentSubscription="); pw.println(mCurrentSubscription);
-        pw.print("      mWakeLock="); pw.println(mWakeLock);
     }
 
     public void setCallback(Callback callback) {
@@ -114,38 +86,26 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
     @Override
     public void onConnected() {
         if (DEBUG) Slog.d(TAG, "onConnected");
-        mAlarmManager = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
-        final PowerManager p = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
-        mWakeLock = p.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
         mLookaheadThreshold = mContext.getResources()
                 .getInteger(R.integer.config_next_alarm_condition_lookahead_threshold_hrs) * HOURS;
-        init();
-        mConnected = System.currentTimeMillis();
-    }
-
-    public void onUserSwitched() {
-        if (DEBUG) Slog.d(TAG, "onUserSwitched");
-        if (mConnected != 0) {
-            init();
-        }
+        mConnected = true;
+        mTracker = mCallback.getNextAlarmTracker();
+        mTracker.addCallback(mTrackerCallback);
     }
 
     @Override
     public void onDestroy() {
         super.onDestroy();
         if (DEBUG) Slog.d(TAG, "onDestroy");
-        if (mRegistered) {
-            mContext.unregisterReceiver(mReceiver);
-            mRegistered = false;
-        }
-        mConnected = 0;
+        mTracker.removeCallback(mTrackerCallback);
+        mConnected = false;
     }
 
     @Override
     public void onRequestConditions(int relevance) {
-        if (mConnected == 0 || (relevance & Condition.FLAG_RELEVANT_NOW) == 0) return;
+        if (!mConnected || (relevance & Condition.FLAG_RELEVANT_NOW) == 0) return;
 
-        final AlarmClockInfo nextAlarm = mAlarmManager.getNextAlarmClock(mCurrentUserId);
+        final AlarmClockInfo nextAlarm = mTracker.getNextAlarm();
         if (nextAlarm == null) return;  // no next alarm
         if (mCallback != null && mCallback.isInDowntime()) return;  // prefer downtime condition
         if (!isWithinLookaheadThreshold(nextAlarm)) return;  // alarm not within window
@@ -154,12 +114,6 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
         notifyCondition(newConditionId(), nextAlarm, Condition.STATE_TRUE, "request");
     }
 
-    private boolean isWithinLookaheadThreshold(AlarmClockInfo alarm) {
-        if (alarm == null) return false;
-        final long delta = getEarlyTriggerTime(alarm) - System.currentTimeMillis();
-        return delta > 0 && (mLookaheadThreshold <= 0 || delta < mLookaheadThreshold);
-    }
-
     @Override
     public void onSubscribe(Uri conditionId) {
         if (DEBUG) Slog.d(TAG, "onSubscribe " + conditionId);
@@ -168,73 +122,33 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
             return;
         }
         mCurrentSubscription = conditionId;
-        mHandler.postEvaluate(0);
-    }
-
-    private static long getEarlyTriggerTime(AlarmClockInfo alarm) {
-        return alarm != null ? (alarm.getTriggerTime() - EARLY) : 0;
+        mTracker.evaluate();
     }
 
-    private boolean isDoneWaitingAfterBoot(long time) {
-        if (mBootCompleted > 0) return (time - mBootCompleted) > WAIT_AFTER_BOOT;
-        if (mConnected > 0) return (time - mConnected) > WAIT_AFTER_CONNECT;
-        return true;
-    }
-
-    private void handleEvaluate() {
-        final AlarmClockInfo nextAlarm = mAlarmManager.getNextAlarmClock(mCurrentUserId);
-        final long triggerTime = getEarlyTriggerTime(nextAlarm);
-        final boolean withinThreshold = isWithinLookaheadThreshold(nextAlarm);
-        final long now = System.currentTimeMillis();
-        final boolean booted = isDoneWaitingAfterBoot(now);
-        if (DEBUG) Slog.d(TAG, "handleEvaluate mCurrentSubscription=" + mCurrentSubscription
-                + " nextAlarm=" + formatAlarmDebug(triggerTime)
-                + " withinThreshold=" + withinThreshold
-                + " booted=" + booted);
-        if (mCurrentSubscription == null) return;  // no one cares
-        if (!booted) {
-            // we don't know yet
-            notifyCondition(mCurrentSubscription, nextAlarm, Condition.STATE_UNKNOWN, "!booted");
-            final long recheckTime = (mBootCompleted > 0 ? mBootCompleted : now) + WAIT_AFTER_BOOT;
-            rescheduleAlarm(recheckTime);
-            return;
-        }
-        if (!withinThreshold) {
-            // triggertime invalid or in the past, condition = false
-            notifyCondition(mCurrentSubscription, nextAlarm, Condition.STATE_FALSE, "!within");
+    @Override
+    public void onUnsubscribe(Uri conditionId) {
+        if (DEBUG) Slog.d(TAG, "onUnsubscribe " + conditionId);
+        if (conditionId != null && conditionId.equals(mCurrentSubscription)) {
             mCurrentSubscription = null;
-            return;
         }
-        // triggertime in the future, condition = true, schedule alarm
-        notifyCondition(mCurrentSubscription, nextAlarm, Condition.STATE_TRUE, "within");
-        rescheduleAlarm(triggerTime);
     }
 
-    private static String formatDuration(long millis) {
-        final StringBuilder sb = new StringBuilder();
-        TimeUtils.formatDuration(millis, sb);
-        return sb.toString();
+    public void attachBase(Context base) {
+        attachBaseContext(base);
     }
 
-    private void rescheduleAlarm(long time) {
-        if (DEBUG) Slog.d(TAG, "rescheduleAlarm " + time);
-        final AlarmManager alarms = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
-        final PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext, REQUEST_CODE,
-                new Intent(ACTION_TRIGGER)
-                        .addFlags(Intent.FLAG_RECEIVER_FOREGROUND)
-                        .putExtra(EXTRA_TRIGGER, time),
-                PendingIntent.FLAG_UPDATE_CURRENT);
-        alarms.cancel(pendingIntent);
-        mScheduledAlarmTime = time;
-        if (time > 0) {
-            if (DEBUG) Slog.d(TAG, String.format("Scheduling alarm for %s (in %s)",
-                    formatAlarmDebug(time), formatDuration(time - System.currentTimeMillis())));
-            alarms.setExact(AlarmManager.RTC_WAKEUP, time, pendingIntent);
-        }
+    public IConditionProvider asInterface() {
+        return (IConditionProvider) onBind(null);
+    }
+
+    private boolean isWithinLookaheadThreshold(AlarmClockInfo alarm) {
+        if (alarm == null) return false;
+        final long delta = NextAlarmTracker.getEarlyTriggerTime(alarm) - System.currentTimeMillis();
+        return delta > 0 && (mLookaheadThreshold <= 0 || delta < mLookaheadThreshold);
     }
 
     private void notifyCondition(Uri id, AlarmClockInfo alarm, int state, String reason) {
-        final String formattedAlarm = alarm == null ? "" : formatAlarm(alarm.getTriggerTime());
+        final String formattedAlarm = alarm == null ? "" : mTracker.formatAlarm(alarm);
         if (DEBUG) Slog.d(TAG, "notifyCondition " + Condition.stateToString(state)
                 + " alarm=" + formattedAlarm + " reason=" + reason);
         notifyCondition(new Condition(id,
@@ -243,28 +157,11 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
                 formattedAlarm, 0, state, Condition.FLAG_RELEVANT_NOW));
     }
 
-    @Override
-    public void onUnsubscribe(Uri conditionId) {
-        if (DEBUG) Slog.d(TAG, "onUnsubscribe " + conditionId);
-        if (conditionId != null && conditionId.equals(mCurrentSubscription)) {
-            mCurrentSubscription = null;
-            rescheduleAlarm(0);
-        }
-    }
-
-    public void attachBase(Context base) {
-        attachBaseContext(base);
-    }
-
-    public IConditionProvider asInterface() {
-        return (IConditionProvider) onBind(null);
-    }
-
     private Uri newConditionId() {
         return new Uri.Builder().scheme(Condition.SCHEME)
                 .authority(ZenModeConfig.SYSTEM_AUTHORITY)
                 .appendPath(NEXT_ALARM_PATH)
-                .appendPath(Integer.toString(mCurrentUserId))
+                .appendPath(Integer.toString(mTracker.getCurrentUserId()))
                 .build();
     }
 
@@ -273,81 +170,41 @@ public class NextAlarmConditionProvider extends ConditionProviderService {
                 && conditionId.getAuthority().equals(ZenModeConfig.SYSTEM_AUTHORITY)
                 && conditionId.getPathSegments().size() == 2
                 && conditionId.getPathSegments().get(0).equals(NEXT_ALARM_PATH)
-                && conditionId.getPathSegments().get(1).equals(Integer.toString(mCurrentUserId));
+                && conditionId.getPathSegments().get(1)
+                        .equals(Integer.toString(mTracker.getCurrentUserId()));
     }
 
-    private void init() {
-        if (mRegistered) {
-            mContext.unregisterReceiver(mReceiver);
+    private void onEvaluate(AlarmClockInfo nextAlarm, long wakeupTime, boolean booted) {
+        final boolean withinThreshold = isWithinLookaheadThreshold(nextAlarm);
+        if (DEBUG) Slog.d(TAG, "onEvaluate mCurrentSubscription=" + mCurrentSubscription
+                + " nextAlarmWakeup=" + mTracker.formatAlarmDebug(wakeupTime)
+                + " withinThreshold=" + withinThreshold
+                + " booted=" + booted);
+        if (mCurrentSubscription == null) return;  // no one cares
+        if (!booted) {
+            // we don't know yet
+            notifyCondition(mCurrentSubscription, nextAlarm, Condition.STATE_UNKNOWN, "!booted");
+            return;
         }
-        mCurrentUserId = ActivityManager.getCurrentUser();
-        final IntentFilter filter = new IntentFilter();
-        filter.addAction(AlarmManager.ACTION_NEXT_ALARM_CLOCK_CHANGED);
-        filter.addAction(ACTION_TRIGGER);
-        filter.addAction(Intent.ACTION_TIME_CHANGED);
-        filter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
-        filter.addAction(Intent.ACTION_BOOT_COMPLETED);
-        mContext.registerReceiverAsUser(mReceiver, new UserHandle(mCurrentUserId), filter, null,
-                null);
-        mRegistered = true;
-        mHandler.postEvaluate(0);
-    }
-
-    private String formatAlarm(long time) {
-        return formatAlarm(time, "Hm", "hma");
-    }
-
-    private String formatAlarm(long time, String skeleton24, String skeleton12) {
-        final String skeleton = DateFormat.is24HourFormat(mContext) ? skeleton24 : skeleton12;
-        final String pattern = DateFormat.getBestDateTimePattern(Locale.getDefault(), skeleton);
-        return DateFormat.format(pattern, time).toString();
-    }
-
-    private String formatAlarmDebug(AlarmClockInfo alarm) {
-        return formatAlarmDebug(alarm != null ? alarm.getTriggerTime() : 0);
-    }
-
-    private String formatAlarmDebug(long time) {
-        if (time <= 0) return Long.toString(time);
-        return String.format("%s (%s)", time, formatAlarm(time, "Hms", "hmsa"));
+        if (!withinThreshold) {
+            // next alarm outside threshold or in the past, condition = false
+            notifyCondition(mCurrentSubscription, nextAlarm, Condition.STATE_FALSE, "!within");
+            mCurrentSubscription = null;
+            return;
+        }
+        // next alarm in the future and within threshold, condition = true
+        notifyCondition(mCurrentSubscription, nextAlarm, Condition.STATE_TRUE, "within");
     }
 
-    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
+    private final NextAlarmTracker.Callback mTrackerCallback = new NextAlarmTracker.Callback() {
         @Override
-        public void onReceive(Context context, Intent intent) {
-            final String action = intent.getAction();
-            if (DEBUG) Slog.d(TAG, "onReceive " + action);
-            long delay = 0;
-            if (action.equals(AlarmManager.ACTION_NEXT_ALARM_CLOCK_CHANGED)) {
-                delay = NEXT_ALARM_UPDATE_DELAY;
-                if (DEBUG) Slog.d(TAG, String.format("  next alarm for user %s: %s",
-                        mCurrentUserId,
-                        formatAlarmDebug(mAlarmManager.getNextAlarmClock(mCurrentUserId))));
-            } else if (action.equals(Intent.ACTION_BOOT_COMPLETED)) {
-                mBootCompleted = System.currentTimeMillis();
-            }
-            mHandler.postEvaluate(delay);
-            mWakeLock.acquire(delay + 5000);  // stay awake during evaluate
+        public void onEvaluate(AlarmClockInfo nextAlarm, long wakeupTime, boolean booted) {
+            NextAlarmConditionProvider.this.onEvaluate(nextAlarm, wakeupTime, booted);
         }
     };
 
     public interface Callback {
         boolean isInDowntime();
-    }
-
-    private class H extends Handler {
-        private static final int MSG_EVALUATE = 1;
-
-        public void postEvaluate(long delay) {
-            removeMessages(MSG_EVALUATE);
-            sendEmptyMessageDelayed(MSG_EVALUATE, delay);
-        }
-
-        @Override
-        public void handleMessage(Message msg) {
-            if (msg.what == MSG_EVALUATE) {
-                handleEvaluate();
-            }
-        }
+        NextAlarmTracker getNextAlarmTracker();
     }
 }
diff --git a/services/core/java/com/android/server/notification/NextAlarmTracker.java b/services/core/java/com/android/server/notification/NextAlarmTracker.java
new file mode 100644
index 000000000000..d197afd3f9d7
--- /dev/null
+++ b/services/core/java/com/android/server/notification/NextAlarmTracker.java
@@ -0,0 +1,263 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.notification;
+
+import android.app.ActivityManager;
+import android.app.AlarmManager;
+import android.app.AlarmManager.AlarmClockInfo;
+import android.app.PendingIntent;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Handler;
+import android.os.Message;
+import android.os.PowerManager;
+import android.os.UserHandle;
+import android.text.format.DateFormat;
+import android.util.Log;
+import android.util.Slog;
+import android.util.TimeUtils;
+
+import com.android.server.notification.NotificationManagerService.DumpFilter;
+
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Locale;
+
+/** Helper for tracking updates to the current user's next alarm. */
+public class NextAlarmTracker {
+    private static final String TAG = "NextAlarmTracker";
+    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
+
+    private static final String ACTION_TRIGGER = TAG + ".trigger";
+    private static final String EXTRA_TRIGGER = "trigger";
+    private static final int REQUEST_CODE = 100;
+
+    private static final long SECONDS = 1000;
+    private static final long MINUTES = 60 * SECONDS;
+    private static final long NEXT_ALARM_UPDATE_DELAY = 1 * SECONDS;  // treat clear+set as update
+    private static final long EARLY = 5 * SECONDS;  // fire early, ensure alarm stream is unmuted
+    private static final long WAIT_AFTER_INIT = 5 * MINUTES;// for initial alarm re-registration
+    private static final long WAIT_AFTER_BOOT = 20 * SECONDS;  // for initial alarm re-registration
+
+    private final Context mContext;
+    private final H mHandler = new H();
+    private final ArrayList<Callback> mCallbacks = new ArrayList<Callback>();
+
+    private long mInit;
+    private boolean mRegistered;
+    private AlarmManager mAlarmManager;
+    private int mCurrentUserId;
+    private long mScheduledAlarmTime;
+    private long mBootCompleted;
+    private PowerManager.WakeLock mWakeLock;
+
+    public NextAlarmTracker(Context context) {
+        mContext = context;
+    }
+
+    public void dump(PrintWriter pw, DumpFilter filter) {
+        pw.println("    NextAlarmTracker:");
+        pw.print("      len(mCallbacks)="); pw.println(mCallbacks.size());
+        pw.print("      mRegistered="); pw.println(mRegistered);
+        pw.print("      mInit="); pw.println(mInit);
+        pw.print("      mBootCompleted="); pw.println(mBootCompleted);
+        pw.print("      mCurrentUserId="); pw.println(mCurrentUserId);
+        pw.print("      mScheduledAlarmTime="); pw.println(formatAlarmDebug(mScheduledAlarmTime));
+        pw.print("      mWakeLock="); pw.println(mWakeLock);
+    }
+
+    public void addCallback(Callback callback) {
+        mCallbacks.add(callback);
+    }
+
+    public void removeCallback(Callback callback) {
+        mCallbacks.remove(callback);
+    }
+
+    public int getCurrentUserId() {
+        return mCurrentUserId;
+    }
+
+    public AlarmClockInfo getNextAlarm() {
+        return mAlarmManager.getNextAlarmClock(mCurrentUserId);
+    }
+
+    public void onUserSwitched() {
+        reset();
+    }
+
+    public void init() {
+        mAlarmManager = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
+        final PowerManager p = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
+        mWakeLock = p.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
+        mInit = System.currentTimeMillis();
+        reset();
+    }
+
+    public void reset() {
+        if (mRegistered) {
+            mContext.unregisterReceiver(mReceiver);
+        }
+        mCurrentUserId = ActivityManager.getCurrentUser();
+        final IntentFilter filter = new IntentFilter();
+        filter.addAction(AlarmManager.ACTION_NEXT_ALARM_CLOCK_CHANGED);
+        filter.addAction(ACTION_TRIGGER);
+        filter.addAction(Intent.ACTION_TIME_CHANGED);
+        filter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
+        filter.addAction(Intent.ACTION_BOOT_COMPLETED);
+        mContext.registerReceiverAsUser(mReceiver, new UserHandle(mCurrentUserId), filter, null,
+                null);
+        mRegistered = true;
+        evaluate();
+    }
+
+    public void destroy() {
+        if (mRegistered) {
+            mContext.unregisterReceiver(mReceiver);
+            mRegistered = false;
+        }
+    }
+
+    public void evaluate() {
+        mHandler.postEvaluate(0);
+    }
+
+    private void fireEvaluate(AlarmClockInfo nextAlarm, long wakeupTime, boolean booted) {
+        for (Callback callback : mCallbacks) {
+            callback.onEvaluate(nextAlarm, wakeupTime, booted);
+        }
+    }
+
+    private void handleEvaluate() {
+        final AlarmClockInfo nextAlarm = mAlarmManager.getNextAlarmClock(mCurrentUserId);
+        final long triggerTime = getEarlyTriggerTime(nextAlarm);
+        final long now = System.currentTimeMillis();
+        final boolean alarmUpcoming = triggerTime > now;
+        final boolean booted = isDoneWaitingAfterBoot(now);
+        if (DEBUG) Slog.d(TAG, "handleEvaluate nextAlarm=" + formatAlarmDebug(triggerTime)
+                + " alarmUpcoming=" + alarmUpcoming
+                + " booted=" + booted);
+        fireEvaluate(nextAlarm, triggerTime, booted);
+        if (!booted) {
+            // recheck after boot
+            final long recheckTime = (mBootCompleted > 0 ? mBootCompleted : now) + WAIT_AFTER_BOOT;
+            rescheduleAlarm(recheckTime);
+            return;
+        }
+        if (alarmUpcoming) {
+            // wake up just before the next alarm
+            rescheduleAlarm(triggerTime);
+        }
+    }
+
+    public static long getEarlyTriggerTime(AlarmClockInfo alarm) {
+        return alarm != null ? (alarm.getTriggerTime() - EARLY) : 0;
+    }
+
+    private boolean isDoneWaitingAfterBoot(long time) {
+        if (mBootCompleted > 0) return (time - mBootCompleted) > WAIT_AFTER_BOOT;
+        if (mInit > 0) return (time - mInit) > WAIT_AFTER_INIT;
+        return true;
+    }
+
+    private static String formatDuration(long millis) {
+        final StringBuilder sb = new StringBuilder();
+        TimeUtils.formatDuration(millis, sb);
+        return sb.toString();
+    }
+
+    public String formatAlarm(AlarmClockInfo alarm) {
+        return alarm != null ? formatAlarm(alarm.getTriggerTime()) : null;
+    }
+
+    private String formatAlarm(long time) {
+        return formatAlarm(time, "Hm", "hma");
+    }
+
+    private String formatAlarm(long time, String skeleton24, String skeleton12) {
+        final String skeleton = DateFormat.is24HourFormat(mContext) ? skeleton24 : skeleton12;
+        final String pattern = DateFormat.getBestDateTimePattern(Locale.getDefault(), skeleton);
+        return DateFormat.format(pattern, time).toString();
+    }
+
+    private String formatAlarmDebug(AlarmClockInfo alarm) {
+        return formatAlarmDebug(alarm != null ? alarm.getTriggerTime() : 0);
+    }
+
+    public String formatAlarmDebug(long time) {
+        if (time <= 0) return Long.toString(time);
+        return String.format("%s (%s)", time, formatAlarm(time, "Hms", "hmsa"));
+    }
+
+    private void rescheduleAlarm(long time) {
+        if (DEBUG) Slog.d(TAG, "rescheduleAlarm " + time);
+        final AlarmManager alarms = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
+        final PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext, REQUEST_CODE,
+                new Intent(ACTION_TRIGGER)
+                        .addFlags(Intent.FLAG_RECEIVER_FOREGROUND)
+                        .putExtra(EXTRA_TRIGGER, time),
+                PendingIntent.FLAG_UPDATE_CURRENT);
+        alarms.cancel(pendingIntent);
+        mScheduledAlarmTime = time;
+        if (time > 0) {
+            if (DEBUG) Slog.d(TAG, String.format("Scheduling alarm for %s (in %s)",
+                    formatAlarmDebug(time), formatDuration(time - System.currentTimeMillis())));
+            alarms.setExact(AlarmManager.RTC_WAKEUP, time, pendingIntent);
+        }
+    }
+
+    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            final String action = intent.getAction();
+            if (DEBUG) Slog.d(TAG, "onReceive " + action);
+            long delay = 0;
+            if (action.equals(AlarmManager.ACTION_NEXT_ALARM_CLOCK_CHANGED)) {
+                delay = NEXT_ALARM_UPDATE_DELAY;
+                if (DEBUG) Slog.d(TAG, String.format("  next alarm for user %s: %s",
+                        mCurrentUserId,
+                        formatAlarmDebug(mAlarmManager.getNextAlarmClock(mCurrentUserId))));
+            } else if (action.equals(Intent.ACTION_BOOT_COMPLETED)) {
+                mBootCompleted = System.currentTimeMillis();
+            }
+            mHandler.postEvaluate(delay);
+            mWakeLock.acquire(delay + 5000);  // stay awake during evaluate
+        }
+    };
+
+    private class H extends Handler {
+        private static final int MSG_EVALUATE = 1;
+
+        public void postEvaluate(long delay) {
+            removeMessages(MSG_EVALUATE);
+            sendEmptyMessageDelayed(MSG_EVALUATE, delay);
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            if (msg.what == MSG_EVALUATE) {
+                handleEvaluate();
+            }
+        }
+    }
+
+    public interface Callback {
+        void onEvaluate(AlarmClockInfo nextAlarm, long wakeupTime, boolean booted);
+    }
+}